I have read up on all of the threads I could find with similar issues. I have a 2003 disco, and am having an flicker in my battery light at dash. I have new plugs, wires, and have checked alternator under load and at idle, checked all fuses and wires. All seems within range. I am getting no codes, other than a P1416 which was a P1412, until I tested a SAI valve and moved it to see if it switched codes and banks. It did, valve ordered.
So no code, just a flickering battery light. It tends to happen when engine is warm and I am cruising and accelerate to pass on highway, or really gun the engine....
Any ideas or insight would be appreciated.

 

On the passenger side, behind the alternator is a ground wire bolted near the heater hose to the engine. Might just check it for tightness. Careful if battery is connected, likes to spark if you touch the right wire. :-)

 

I would check and clean all ground wires, battery posts first. Check the belt to see if it is hard and cracking. I would also go to Harbor Freight(if you have one near) and purchase this little gadget for 4.99. It can be used to check voltage, alternator, and i use it to check fuses.

 

i just saw that at harbor freight last night
is your tachometer fluctuating at the same time?

 

Thank you for ideas and input... Tach is not fluctuating. I have had alternator tested, and it tested well. I will revisit all grounds and battery connections. Belt is new within a year and looks good.
Haven't checked all pulleys, wonder if that might be source?